Rotary jar



Sept. 26, 1933. F. J. Klear-rmNGER` ROTARY JAR Y H//////////////\ j .1....,........|.......H-. .LL.-

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Patented Sept. 26, 1933 UNITED STATES PATENT orns Application February 3, 1931.

Serial No. 513,073

3 Claims'. (Cl. Z55-27) This invention has to do with jars such as are especially adapted for use in connection with rotary well drilling equipment and has as its primary object the production of a jar of this 5 nature which is of simple form and construction, positive in operation, and may be brought into use at any time during the drilling operation.

It is well known to those familiar with the rart that during oil well drilling operations it is a more or less frequent occurrence to have the bit become stuck or hung up in the well. In the use of rotary drilling equipment this frequently occurs when the rotation of the bit is stopped for a brief period and the rotary mud and cavings from the well settle about the bit. It is necessary in avoiding this to maintain circulation of the rotary mud or water through the drilling equipment, but even while maintaining such circulation the bits frequently become stuck and require the use of auxiliary equipment to dislodge them.

The most common form of equipment used under these circumstances is known as the rotary jar which ordinarily consists in a general way of a pair of telescoping members, one of which is attached to the bit end of the drill stem and the other end of which is attached to the upper or drive section of the drill stem. Some of these jars may be used in connection with a fishing tool, others are interposed directly in the drill stem for use in the event of an emergency. Some of the jars are constructed so that they must be set before they enter a well and such jars can be used but a single time and then must be Withdrawn for resetting. Other forms of jars have been constructed with an effort to provide a device which must be operated any number of times without removing it from the well for resetting. The most common form of such jars depends for its operation upon the twisting ofthe drill stem. This places excessive torsional strain on the pipes comprising the drill stem and for this reason has met with some criticism in the oil well drilling art.

jar which may be inserted in the drill stem and through which the bit may be driven from the drill stem without lost motion.

It is a further object of this invention to produce a jar which may be operated any number of times while the drill stem is in the well.

With these objects in view the device contemplated by this invention. utilizes a non-compressible fluid in a manner such that the jar may bel It is an object of this invention to produce al companying drawing which is chosen for illusused rapidly at any time during the drilling operation without placing the drill stem under torsional strain.

The general construction of the jar contemplated by this invention embodies a cylinder mem- 50 ber which contains a fluid filled chamber and which is adapted to be connected to one section of the drill stem. A mandrel is attached to the other section of the drill stem and this mandrel slidably extends through an impact sub on the cylinder member and through the chamber in the cylinder member. A pistonis mounted on the mandrel in the chamber and means are provided for permitting a restricted flow of the fluid in the chamber from one end of the chamber to the o other during an initial movement of the piston and for permitting a non-restricted iiow of the fluid between the ends of the chamber during a final movement of the piston; In other words! assuming the jar to be mounted in the drill stemv for giving an upward jar to the fish at the lower end of the stem, an upward pull applied to the mandrel places the drill string under tension and tends to move the piston in the chamber upwardly. This upward movement is retarded by the restricted ilow of fluid between the ends of the chamber until the piston reaches a predetermined point at which the fluid rushes from the upper end of the chamber to the lower end of the chamber and the piston is jerked upwardly so that impact shoulders provided in the two members will be jerked into engagement and produce the desired jar. The flow of uid between the ends of the chamber is preferably governed by passages and ports in the wall of the cylinder member, but might be controlled by means of suitable ports and valves associated with the piston.

It is a noteworthy feature of this invention that the chamber is provided with a valve which opens during the return stroke of the piston and greatly reduces the time required in setting the jar or placing the parts in position for a second jarring operation.

The details in the construction of a preferred form vof my invention, together with other objects attending its production, will be best understood from the following description of the actrative purposes only,'and in which Fig. 1 is a sectional elevation taken through a preferred form of my invention and illustrating the parts arranged for the initiation `oi' a jarring., operation;

Fig. 2 is an enlarged partial sectional elevation taken in a plane at right angles to the` section plane of Fig. 1 'm the direction of the arrow 2, and shows the plunger as having been moved upwardly to a point just prior to the engagement of the impact shoulders;

Fig. 3 is a plan section taken in the plane represented by the line 3-3 in Fig. 2;

Fig. 4 is an invertedplan section taken in a plane represented by the line 4-4 in Fig. 2; and

Fig. 5 is an enlarged sectional view illustrating details in the construction of the lower end of the chamber in Fig. 1.

More particularly describing the invention as herein illustrated, reference numeral 11 indicates what I have termed a cylinder member which is provided with a longitudinal passage l2 and an enlarged fluid iilled chamber 13. The upper end of the cylinder member or barrel 11 is in threaded engagement with an impact sub 14 and this sub 14 is threaded to receive a bushing member 15 which forms a part of a packing gland 16 through which a mandrel 17 slidably extends. The upper end of the mandrel i7 is in threaded engagement with a sub 18 which has a threaded male portion 19 adapted for attachment to a collar on the lower end of a drill stem. section indicated by reference numeral 20.

The mandrel l'l is shown as having a reduced portion 2l contained within the chamber 13 and such portion receives a piston 22. The piston 22 is shown as being comprised of a rubber portion 23 and metal end rings 24 and 25. The end ring 24 engages a shoulder 26 on the mandrel and the entire piston is pressed upwardly toward the shoulder 26 by means of a nut 27 which is in threaded engagement with the reduced portion 21 of the mandrel.

It will also be noted that the mandrel is provided with a fluid passage 28 whereby circulating iiuid may be carried between the sections of the drill stem to which the mandrel and the cylinder are attached.

The lower end portion of the cylinder member ll is threaded as indicated at 29 for engagement with a sub 30 by means of which the cylinder may be attached to a section of the drill stem. The mandrel is shown as being provided with a second reduced portion 31 which may be formed directly on the main mandrel member 17 or may be formed as a separate piece of tubing which is threaded into the lower end of the mandrelmember. This portion 31 extends through a packing gland 32 interposed between the sub 30 -and the lower end of the cylinder member and is used to deliver the circulating fluid which is carried by the passage 28 into the section of drill stem which is mounted on the lower end of the sub 30.

It was pointed out in the fore part of the speciiication that this jar depended for its operation upon the restricted flow of fluid between the ends of the chamber during an initial movement of the piston 22 and a non-restricted flow of fluid between the ends of the chamber 13 during a final movement of the piston. The ilow of fluid between the ends of the chamber 13 takes place through a passage 35 which is provided in the cylinder wall and has a port 36 `communicating with the upper end of the chamber 13. Reference numeral 37 indicates a port at the lower end of the passage 35 which communicates with the chamber 13 below the piston 22. This port will be hereinafter referred to as a restricted port and is made of a much smaller cross sectional area than the port 36 so that the flow of fluid resulting from the application of pressure to the iiuid from the piston 22 will be materially retarded during the initial upward movement o! the piston. -In this manner an upward force applied to the drill stem section 20 will tend to pull the piston 22 upwardly through the chamber 13, but since this movement is retarded by the restricted flow of iiuid through the passage 37 the force, if rapidly applied, will place the drill stem section 20 under considerable tension. The piston 22, however, gradually moves upwardly until it passes a second port 38 which has a cross sectional area that corresponds substantially to the cross sectional area of the port 36. When the piston has moved to this point the iluid rushes from the upper end of the chamber into the lower end of the chamber and the accumulated tension in the drill stem, together with the continued application of upward pull thereto, jerks the mandrel and its associated parts upwardly relative to the cylinder member l1.

In order that this jerk may result in a jar to the section of drill stem which is attached to the cylinder member, it is necessary to provide the cylinder member and the mandrel respectively with cooperating impact shoulders. In this form of my invention it will be noted that that portion of the passage 12 which extends above the chamber 13 is made in the form of a slot or is elliptical in cross section and the mandrel 17 is provided with a T section l0 which corresponds in shape to the elliptical portion of the passage and is received therein. The upper end of this T section 40 forms a shoulder e9 which is positioned on the mandrel so as to engage a shoulder 50 provided on the lower end of the impact sub le. lt is to be understood, of course, that other means might be provided for obtaining the desired im pact at the end of the upward stroke of the piston, but the construction described has the additional function of holding the cylinder member 11 and the mandrel 17 together with its associated parts, including the piston 22, against relalll@ tive rotation so that the lower end. of the drill that the piston after it passes the port 38,

has a completely non-retarded upward movement through the chamber. With this in view the wall of the cylinder member may be provided with an auxiliary passage 51 which has a port 52 positioned opposite the port 36 and a port 53 positioned opposite the port 38. It will be understood, of course, that any number of such passages may be provided to obtain the desired movement of the piston in the chamber. To facilitate the downward movement of the piston after a jarring operation has been completed, I employ a valved port 54 which is shown as being situated at the extreme lower end of the chamber 13 and is provided with a valve 55 which is associated with a spring 56 to permit the outward ilow of uid from the lower end of the chamber into the passage 35 during the downward movement of the piston. This greatly reduces the time required in moving the piston downwardly from the point where the port 38 is closed by the piston to the position shown in Fig. 1.

It will be apparent from the foregoing description that the device contemplated by this invention is of simple form and construction, it may be interposed at any point in a drill stem and 'tao is constructed so that there is no lost motion during the rotation of the drill stem in either direction; the jar may be used at any time and as often as desired during the drilling operation; the direction of the jarring force may be reversed by reversing the position of the jar in the drill stem; and the magnitude of the blow resulting from the engagement of the two impact members may be governed by the distance between the port 38 and the port 36.

It is to be understood that while I have herein described and illustrated one preferred form of my invention, the invention is not limited to the precise construction described above, but includes within its scope whatever changes fairly come within the spirit of the appended claims.

I claim as my invention:

1. A rotary jar embodying: a barrel having a fluid filled piston cylinder` of uniform diameter throughout its length; an impact sub in the top of said barrel; closure means in the bottom of said barrel; a mandrel extending through said impact sub; a piston mounted on said mandrel in said cylinder; and an impact member on said mandrel adapted to engage said impact sub, the wall of said barrel being provided with a tubular passage, said wall also having a port in the top of said cylinder of substantially the same diameter as said tubular passage, a restricted port in the bottom of said cylinder and another port at an intermediate point in said cylinder adapted to be covered by said piston during the initiation of an upward stroke, all of said ports communicating with said tubular passage.

2. A rotary jar embodying: a barrel having a uid filled piston cylinder of uniform diameter throughout its length; an impact sub in the top of said barrel; closure means in the bottom of said barrel; a mandrel extending through said impact sub; a piston mounted on said mandrel in said cylinder; an impact member on said mandrel adapted to engage said impact sub, the wall of said barrel being provided with a tubular passage, said wall also having a port in the top of said cylinder of substantially the same diameter as said tubular passage, a restricted port in the bottom of said cylinder and another port at an intermediate point in said cylinder adapted to be covered by said piston during the initiation of an upward stroke, all of said ports communicating with said tubular passage, said tubular passage having another port in the bottom of said cylinder; and a check valve in said last mentioned port adapted to permit the passage of fluid through said tubular passage from the bottom of said cylinder to the top thereof during a gown stroke of said piston.

3. A rotary jar embodying: a barrel having a fluid lled piston cylinder of uniform diameter throughout its length; an impact sub in the top of said barrel; closure means in the bottom of said barrel; a mandrel extending through said impact sub; a piston mounted on said mandrel in said cylinder; a packing ring on said piston; and an impact member on said mandrel adapted to engage said impact sub, the wall of said barrel being provided with a tubular passage, said wall also having a port in the top of said cylinder of substantially the same diameter as said tubular passage, a restricted port in the bottom of said cylinder and another port at an intermediate point in said cylinder adapted to be covered by said piston during the initiation of an upward stroke, all of said ports communicating with said tubular passage.

'FRANK J. KIGHTLINGER. 

